rdfs:comment
| - Throughout the 1990s, a close relationship between cetaceans and mesonychids, an extinct group of cursorial, wolf-like ungulates, was generally accepted based on morphological analyses. In the late 1990s, however, cladistic analyses based on molecular data clearly placed Cetacea within the Artiodactyla near the hippopotamus. One of the diagnostic characters of artiodactyls are the double-pulley astragalus (heel bone) and palaeontologists, unconvinced by the data from the labs, set themselves out to find archaeocete single-pulley heel bones. Hind legs from three archaeocete species were recovered within a few years, among them those of Rodhocetus balochistanensis, and these cetaceans all had double-pulley heel bones — the cladistic controversy was finally settled.[4]
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abstract
| - Throughout the 1990s, a close relationship between cetaceans and mesonychids, an extinct group of cursorial, wolf-like ungulates, was generally accepted based on morphological analyses. In the late 1990s, however, cladistic analyses based on molecular data clearly placed Cetacea within the Artiodactyla near the hippopotamus. One of the diagnostic characters of artiodactyls are the double-pulley astragalus (heel bone) and palaeontologists, unconvinced by the data from the labs, set themselves out to find archaeocete single-pulley heel bones. Hind legs from three archaeocete species were recovered within a few years, among them those of Rodhocetus balochistanensis, and these cetaceans all had double-pulley heel bones — the cladistic controversy was finally settled.[4] Through a principal components analysis Gingerich 2003 demonstrated that Rodhocetus had trunk and limb proportions similar to the Russian desman, a foot-powered swimmer using its tail mainly as a rudder. From this Gingerich concluded that Rodhocetus was swimming mostly at the surface by alternate strokes of its hind feet, and that it was insulated by fur rather than blubber, as are Dorudon and modern cetaceans, which made it buoyant and incapable of deep diving.
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